What is the value of x?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

In which direction does the left side of the graph of this function point? f(x) = 3x3 - x2 + 4x - 2

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.